一种新型的电流源型变流器PWM控制策略及其在超导磁储能装置中的应用

A Novel PWM Control for Current Source Converter and Its Application in a Superconducting Magnetic Energy Storage Unit

超导磁储磁能(SMES)装置的超导磁体通过变流器与电网连接,为了减小装置向系统注入的谐波电流,各种改进的脉宽调制(PWM)技术被用于变流器的控制。该文分别用正弦波和三角波作为调制和载波信号,提出一种可用于电流源型变流器的实时电流控制的新型PWM开关策略,并在此基础上研究了能够按照系统要求对电流源型SMES独立地进行有功和无功功率四象限调节的实时功率控制方法。仿真结果表明,该开关策略不仅能够快速改变变流器交流侧电流的幅值和相位,有效降低变流器交流侧电流中的谐波含量,而且能够提高SMES装置的功率响应特性。同时该方法还具有控制策略简单,工程实现容易的特点。

The superconducting magnet in a superconducting magnetic energy storage （SMES） unit connects with the power system by a converter. Different kinds of improved pulse width modulation （pWM） technologies are used in the converter to reduce the harmonic injected by the SMES unit to the power system. Using a sinusoidal wave and a triangle wave as the modulation signals and carrier signal respectively, a new kind of PWM switching strategy for the current instantaneous control of the current source converter is proposed. Based on the switching strategy proposed, a real-time power control method used to independently regulate the active and the reactive power exchanging between the superconducting magnet and the interconnected power system according to the requirements of the system is studied. Simulation results show that the switching strategy proposed is able to quickly change the magnitude and phase angle of the AC current output of the converter. The additional advantages of the proposed switching strategy are that the harmonic produced by the converter is reduced effectively and the response characteristics of the CSMES in power exchanging is improved. Also, as the proposed method is simple, it can be easily realized in the practice.